Why Warehouses Have Asbestos
Asbestos cement was one of the most popular roofing and cladding materials for industrial buildings from the 1950s to the 1990s. It was cheap, durable, fire-resistant, and easy to install — making it a default choice for warehouses, distribution centres, factories, and other large-footprint industrial buildings across Ireland and Northern Ireland. Many of those roofs are still in service today.
Asbestos cement typically contains 10–15% chrysotile (white asbestos) mixed with Portland cement. While lower in risk than loose asbestos lagging or insulating board, asbestos cement still poses a health hazard when fibres are released — which happens through weathering, physical damage, cutting, drilling, or any work that disturbs the material.
The typical warehouse built between 1960 and 1990 has asbestos cement roofing sheets (corrugated profile), asbestos cement wall cladding, and potentially asbestos-containing materials in soffits, gutters, downpipes, and flashings. The legal duty to identify, assess and control asbestos applies to all of it.
The Warehouse Challenge: Height, Area, Operations
Warehouses present specific challenges for asbestos management that differ from smaller commercial buildings:
Working at Height
Warehouse eaves heights typically range from 6m to 15m. Interior spray foam application requires cherry pickers, boom lifts, or scissor lifts to reach the underside of the roof. This equipment requires clear floor space for positioning, which means racking and stored goods may need to be moved in sections. Duratite programmes interior works in phases to minimise stock displacement.
Large Roof Areas
A typical warehouse has 1,000–5,000m² of roof area, and large distribution centres can exceed 20,000m². The scale benefits from economies — per-square-metre costs reduce significantly on larger projects — but the logistics of spraying thousands of square metres require careful programming and quality control. Duratite deploys multiple spray rigs on large projects to maintain programme.
Operational Continuity
Most warehouses cannot simply close for weeks while asbestos is dealt with. Stock commitments, customer deliveries, and contractual obligations require continued operations. This is a major advantage of encapsulation over removal — with interior spray foam, work proceeds in sections while the rest of the warehouse operates normally. With exterior coating, the warehouse interior is entirely unaffected.
Interior Spray Foam Encapsulation
Nexseal LE closed-cell spray foam is applied to the underside of the asbestos cement roof from inside the warehouse. The foam adheres directly to the asbestos cement, creating a continuous, gap-free encapsulation layer that permanently seals all fibres. At the same time, the spray foam provides:
• Thermal insulation — 50–80mm of Nexseal LE (lambda 0.027 W/mK) transforms an uninsulated roof (U-value ~5.0) into a well-insulated one (U-value ~0.35–0.5), cutting heating costs by 30–50%
• Condensation control — the closed-cell foam acts as an integral vapour barrier, eliminating the condensation that plagues uninsulated metal and asbestos cement roofs
• Structural reinforcement — the rigid foam bonds to the underside of the roof sheets, adding structural rigidity and windload resistance
• Sound reduction — dampens rain noise and external sound transmission
Interior spray foam is the preferred approach when the building owner wants the thermal and condensation benefits alongside encapsulation. It is particularly effective for heated warehouses, where the energy savings provide a return on investment that makes the encapsulation effectively self-funding within 3–5 years.
Exterior Silicone Coating Encapsulation
GacoFlex S42/SF42 silicone roof coating is applied to the exterior surface of the asbestos cement roof. The coating encapsulates the exposed surface — the side most prone to weathering and fibre release — while simultaneously providing:
• Waterproofing — seals existing leaks, failed laps, and deteriorated fixings
• UV protection — silicone coating is highly UV stable, protecting the asbestos cement from further photodegradation
• Weather resistance — withstands rain, hail, snow, and temperature extremes
• Appearance improvement — transforms a grey, weathered asbestos cement roof into a clean, uniform finish
Exterior coating is the preferred approach when the building does not require thermal insulation (unheated warehouses, ambient storage), when interior access is restricted by high-bay racking that cannot be moved, or when the primary objectives are encapsulation and waterproofing rather than thermal upgrade.
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Choosing the Right System
| Factor | Interior Spray Foam (Nexseal LE) | Exterior Coating (GacoFlex S42/SF42) |
|---|---|---|
| Encapsulation | ✓ Full underside encapsulation | ✓ Full external encapsulation |
| Thermal insulation | ✓ Excellent (U-value 0.35–0.5) | ✗ Minimal |
| Condensation control | ✓ Eliminates condensation | ✗ No effect on condensation |
| Waterproofing | ✗ No external waterproofing | ✓ Full roof waterproofing |
| UV protection | ✗ Not applicable (interior) | ✓ Excellent UV barrier |
| Structural reinforcement | ✓ Adds rigidity | ✗ Minimal |
| Building disruption | Moderate (phased sections) | None (exterior work only) |
| Weather dependent | No | Yes (dry conditions needed) |
| Relative cost/m² | Higher | Lower |
| Best for | Heated warehouses, condensation issues | Unheated storage, waterproofing needs |
For maximum protection, the two systems can be combined — Nexseal LE on the interior for thermal insulation and condensation control, GacoFlex S42/SF42 on the exterior for waterproofing and UV protection. This "belt and braces" approach encapsulates the asbestos from both sides and delivers the complete range of building performance improvements.
Condensation and Thermal Benefits
Condensation is one of the most damaging problems in warehouses with asbestos cement roofs, and the mild, wet Irish climate makes it all too common. In cold weather, the uninsulated roof cools to below the dew point of the warm, moist air inside the building. Water vapour condenses on the cold roof underside and drips onto stock, equipment, vehicles, and workers below.
The cost of condensation damage in warehouses is substantial: damaged stock (packaging, electronics, food products are particularly vulnerable), corrosion of racking and equipment, slip hazards, health complaints from workers, and insurance claims. For many warehouse operators, solving the condensation problem is as important as managing the asbestos.
Interior spray foam encapsulation with Nexseal LE solves both problems simultaneously. The foam raises the surface temperature of the roof underside above the dew point, eliminating condensation. At the same time, the thermal insulation reduces heating costs by 30–50% and makes the warehouse a more comfortable working environment. The combined benefit — asbestos management, condensation elimination, and energy savings — makes the return on investment compelling.
What Drives Cost for Typical Warehouse Sizes
| Warehouse Size | Typical Considerations | Effect on Price per m² |
|---|---|---|
| 500m² (small unit) | Mobilisation and access are a large share of the cost | Highest per m² |
| 1,000m² (medium warehouse) | Access equipment and phasing around stock | Moderate per m² |
| 2,000m² (large warehouse) | Multiple phases; racking and operations to plan around | Lower per m² |
| 5,000m² (distribution centre) | Multiple spray rigs to hold the programme | Lower still per m² |
| 10,000m²+ (major distribution) | Detailed phasing plan agreed with operations | Lowest per m² |
Every warehouse is priced individually, with a fixed quote after a free site survey. Actual costs depend on roof condition, access requirements, height, and specification, and a combined interior and exterior system costs more than either system alone. Northern Ireland companies may be able to reduce the net cost through Land Remediation Relief; there is no equivalent relief in the Republic of Ireland.
Contact Duratite on info@duratite.ie for a free warehouse survey and fixed-price quotation.